1. Safety and Reliability Analysis
Team KANG
Group 1

2. 10.22 Failures/Million hours MTTF 9.78E4 hours ~ 11.2 years
MC9S12XD Microcontroller Reliability Analysis
λp = (C1πT + C2πE)πQπL (Microcircuit Model)
Parameter
Value
Justification / Assumptions C1
0.280
16 Bit Microprocessor, MOS ([1], Section 5.1) C2
0.077
144 Pin, Nonhermetic SMT Packaging, Value determined by interpolation ([1], Section 5.9) πT
3.1
Digital MOS Device
Assumptions: TJ=125C. ([1], Section 5.8) πE
2.0
Ground Fixed Environment ([1], Section 5.10) πQ
10.0
Commercial Component ([1], Section 5.10) πL
1.0
Years in Production >= 2 ([1], Section 5.10) λp
10.22 Failures/Million hours
MTTF
9.78E4 hours ~ 11.2 years

3. Justification / Assumptions
GAL26CV12 PLD Reliability Analysis
λp = (C1πT + C2πE)πQπL (Microcircuit Model)
Parameter
Value
Justification / Assumptions C1
.0017
PLA, 1000 Gates, MOS ([1], Section 5.1) C2
.013
28 Pin, Nonhermetic DIP Packaging ([1], Section 5.9) πT
3.1
Digital MOS Device
Assumptions: TJ=125C. ([1], Section 5.8) πE
2.0
Ground Fixed Environment ([1], Section 5.10) πQ
10.0
Commercial Component ([1], Section 5.10) πL
1.0
Years in Production >= 2 ([1], Section 5.10) λp
.3127 Failures/ Million hours
MTTF
3.20E6 hours ~ years

4. Justification / Assumptions
TIP122 (Darlington NPN Expitaxial Transistor) Reliability Analysis
λp = λbπTπAπQπE (Transistor Model)
Parameter
Value
Justification / Assumptions λb
.012
NPN, Si MOSFET ([1], Section 6.4) πT
5.1
Assumptions: TJ=125C. ([1], Section 6.4) πA
4.0
Power MOSFET,
Assumption: PR = 6 V * 6 A = 30 W ([1], Section 6.4) πQ
8.0
Assumption: Plastic (worst case scenario) ([1], Section 6.4) πE
6.0
Ground Fixed Environment ([1], Section 6.4) λp
11.75 Failures/Million hours
MTTF
8.51E4 hours ~ 9.7 years

5. MAX3232 Level Translator Reliability Analysis
λp = (C1πT + C2πE)πQπL (Microcircuit Model)
Parameter
Value
Justification / Assumptions C1
0.040
Linear MOS, 399 Transistor count ([1], Section 5.1) C2
0.072
16 Pin, Nonhermetic SMT Packaging ([1], Section 5.9) πT
0.98
Linear MOS Device
Assumptions: TJ= 85C. ([1], Section 5.8) πE
2.0
Ground Fixed Environment ([1], Section 5.10) πQ
10.0
Commercial Component ([1], Section 5.10) πL
1.0
Years in Production >= 2 ([1], Section 5.10) λp
1.83 Failures/Million hours
MTTF
5.46E5 hours ~ 62.3 years

6. Safety Analysis – FUNCTIONAL BLOCKS
A. Microcontroller
B. Sensors
C. Fire Control
D. Motor Control/Motor Driver
E. User Interface
F. Video
G. RAM
H. Power

7. F D E C A B H G

8. Levels of Criticality Criticality Failure Effect Maximum Probability
Low
Device stops functioning or is damaged, but reparable
p ≥ 10-6
High
Irreparable damage to the device and harm to user
p ≤ 10-9

9. Failure No. Failure Mode Possible Causes Failure Effects
Method of Detection
Criticality
Remark A1
MCU Failure
Short of bypass caps
Failure of MCU
Unpredictability of MCU
Dead MCU
Human Damage
Observation
High
Can be lethal to humans B1
Failure of friendly Detection
Failure of IR Transmitter or Receiver
Gun functions as if everything is enemy
Friendlies get shot once motion sensor is tripped in auto-mode B2
Failure of Enemy Detection
Failure of Motion Sensors
Enemy not detected, user at harms way C1
Gun shoots unpredictably
TIP122 failure
MCU failure
User harm
Friendly can get shot even if IR remote works D2
Unpredictable motion of gun
Failure of GAL
Gun can move to friendly and shoot

10. Failure No.
Failure Mode
Possible Causes
Failure Effects
Method of Detection
Criticality
Remark D4
Unpredictable motion of camera
Failure of driver
Failure of GAL
Video Alg run where the camera moves
Enemy Evades
Observation
High E1
User Interface communication failure
MAX3232 failure
Shorted bypass
Manual override failure H3
AC line failure
Bad power splitting
Shorted PCB
Device will be irreparable

11. Questions?